Hydrophobic PTFE Membranes manufactured by ADVANTEC MFS, Inc. are highly resistant to a broad range of aqueous and organic solvents. These hydrophobic membranes are ideal for sterilization of gases and trap aqueous aerosols. PTFE membrane is manufactured in a unique way where polytetrafluorethylene (PTFE) is expanded both uniaxially and biaxially. The resultant membrane is thin, highly porous, and behaves as an absolute retentive membrane.